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  • Author or Editor: John M. Jackson x
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Wendell A. Nuss
,
John ML Bane
,
William T. Thompson
,
Teddy Holt
,
Clive E. Dorman
,
F. Martin Ralph
,
Richard Rotunno
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Joseph B. Klemp
,
William C. Skamarock
,
Roger M. Samelson
,
Audrey M. Rogerson
,
Chris Reason
, and
Peter Jackson

Coastally trapped wind reversals along the U.S. west coast, which are often accompanied by a northward surge of fog or stratus, are an important warm-season forecast problem due to their impact on coastal maritime activities and airport operations. Previous studies identified several possible dynamic mechanisms that could be responsible for producing these events, yet observational and modeling limitations at the time left these competing interpretations open for debate. In an effort to improve our physical understanding, and ultimately the prediction, of these events, the Office of Naval Research sponsored an Accelerated Research Initiative in Coastal Meteorology during the years 1993–98 to study these and other related coastal meteorological phenomena. This effort included two field programs to study coastally trapped disturbances as well as numerous modeling studies to explore key dynamic mechanisms. This paper describes the various efforts that occurred under this program to provide an advancement in our understanding of these disturbances. While not all issues have been solved, the synoptic and mesoscale aspects of these events are considerably better understood.

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Catherine A. Senior
,
John H. Marsham
,
Ségolène Berthou
,
Laura E. Burgin
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Sonja S. Folwell
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Elizabeth J. Kendon
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Cornelia M. Klein
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Richard G. Jones
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Neha Mittal
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David P. Rowell
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Lorenzo Tomassini
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Théo Vischel
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Bernd Becker
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Cathryn E. Birch
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Julia Crook
,
Andrew J. Dougill
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Declan L. Finney
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Richard J. Graham
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Neil C. G. Hart
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Christopher D. Jack
,
Lawrence S. Jackson
,
Rachel James
,
Bettina Koelle
,
Herbert Misiani
,
Brenda Mwalukanga
,
Douglas J. Parker
,
Rachel A. Stratton
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Christopher M. Taylor
,
Simon O. Tucker
,
Caroline M. Wainwright
,
Richard Washington
, and
Martin R. Willet

Abstract

Pan-Africa convection-permitting regional climate model simulations have been performed to study the impact of high resolution and the explicit representation of atmospheric moist convection on the present and future climate of Africa. These unique simulations have allowed European and African climate scientists to understand the critical role that the representation of convection plays in the ability of a contemporary climate model to capture climate and climate change, including many impact-relevant aspects such as rainfall variability and extremes. There are significant improvements in not only the small-scale characteristics of rainfall such as its intensity and diurnal cycle, but also in the large-scale circulation. Similarly, effects of explicit convection affect not only projected changes in rainfall extremes, dry spells, and high winds, but also continental-scale circulation and regional rainfall accumulations. The physics underlying such differences are in many cases expected to be relevant to all models that use parameterized convection. In some cases physical understanding of small-scale change means that we can provide regional decision-makers with new scales of information across a range of sectors. We demonstrate the potential value of these simulations both as scientific tools to increase climate process understanding and, when used with other models, for direct user applications. We describe how these ground-breaking simulations have been achieved under the U.K. Government’s Future Climate for Africa Programme. We anticipate a growing number of such simulations, which we advocate should become a routine component of climate projection, and encourage international coordination of such computationally and human-resource expensive simulations as effectively as possible.

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Randall M. Dole
,
J. Ryan Spackman
,
Matthew Newman
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Gilbert P. Compo
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Catherine A. Smith
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Leslie M. Hartten
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Joseph J. Barsugli
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Robert S. Webb
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Martin P. Hoerling
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Robert Cifelli
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Klaus Wolter
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Christopher D. Barnet
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Maria Gehne
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Ronald Gelaro
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George N. Kiladis
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Scott Abbott
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Elena Akish
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John Albers
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John M. Brown
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Christopher J. Cox
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Lisa Darby
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Gijs de Boer
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Barbara DeLuisi
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Juliana Dias
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Jason Dunion
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Jon Eischeid
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Christopher Fairall
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Antonia Gambacorta
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Brian K. Gorton
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Andrew Hoell
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Janet Intrieri
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Darren Jackson
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Paul E. Johnston
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Richard Lataitis
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Kelly M. Mahoney
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Katherine McCaffrey
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H. Alex McColl
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Michael J. Mueller
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Donald Murray
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Paul J. Neiman
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William Otto
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Ola Persson
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Xiao-Wei Quan
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Imtiaz Rangwala
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Andrea J. Ray
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David Reynolds
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Emily Riley Dellaripa
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Karen Rosenlof
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Naoko Sakaeda
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Prashant D. Sardeshmukh
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Laura C. Slivinski
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Lesley Smith
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Amy Solomon
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Dustin Swales
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Stefan Tulich
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Allen White
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Gary Wick
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Matthew G. Winterkorn
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Daniel E. Wolfe
, and
Robert Zamora

Abstract

Forecasts by mid-2015 for a strong El Niño during winter 2015/16 presented an exceptional scientific opportunity to accelerate advances in understanding and predictions of an extreme climate event and its impacts while the event was ongoing. Seizing this opportunity, the National Oceanic and Atmospheric Administration (NOAA) initiated an El Niño Rapid Response (ENRR), conducting the first field campaign to obtain intensive atmospheric observations over the tropical Pacific during El Niño.

The overarching ENRR goal was to determine the atmospheric response to El Niño and the implications for predicting extratropical storms and U.S. West Coast rainfall. The field campaign observations extended from the central tropical Pacific to the West Coast, with a primary focus on the initial tropical atmospheric response that links El Niño to its global impacts. NOAA deployed its Gulfstream-IV (G-IV) aircraft to obtain observations around organized tropical convection and poleward convective outflow near the heart of El Niño. Additional tropical Pacific observations were obtained by radiosondes launched from Kiritimati , Kiribati, and the NOAA ship Ronald H. Brown, and in the eastern North Pacific by the National Aeronautics and Space Administration (NASA) Global Hawk unmanned aerial system. These observations were all transmitted in real time for use in operational prediction models. An X-band radar installed in Santa Clara, California, helped characterize precipitation distributions. This suite supported an end-to-end capability extending from tropical Pacific processes to West Coast impacts. The ENRR observations were used during the event in operational predictions. They now provide an unprecedented dataset for further research to improve understanding and predictions of El Niño and its impacts.

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